Canister purge systems for automotive vehicles which are powered by gasoline-fueled internal combustion engines are of course well known. The fuel tank's headspace is placed in communication with a vapor collection canister that collects volatile fuel vapors generated in the tank. The canister is selectively purged to the engine intake manifold under conditions conducive to purging. To minimize the potential for liquid fuel escaping the tank via the canister purge system in the event of an accident such as a vehicle roll-over, a roll-over valve is associated with the tank and canister to close the passage between them when such an event occurs. Such roll-over valve is typically mounted on the tank itself, and in addition to closing in response to tipping of the vehicle, and hence also of the fuel tank, beyond a certain range from the vertical, it also is buoyed closed if the liquid fuel in the tank rises to the valve.
Canister purge systems are now in the process of being equipped with on-board diagnostic systems. One type of on-board diagnostic system uses a pressure sensor for sensing pressure, either positive and/or negative, in the tank headspace.
The present invention relates to an improvement for the combination of such pressure sensing and roll-over closure functions in a single assembly for mounting on a fuel tank. The present invention makes use of the already existing requirement for an opening in a top wall portion of the tank to mount a roll-over valve, and consequently eliminates the need for an additional opening in the tank wall in order to communicate the pressure sensor to the tank headspace. The elimination of such an extra opening has obvious advantages for automotive vehicle manufacturers. A single sealing grommet is used to mount the assembly in a single opening in the tank wall. Furthermore, the invention offers the possibility for lower component and assembly costs because only a single component need be ordered and installed by the automotive vehicle manufacturer in order to incorporate both the pressure sensing function and the roll-over valve function.
Further features, advantages, and benefits of the invention, along with those just mentioned, will be seen in the ensuing description and claims. Drawings accompany the disclosure and illustrate a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.